The California Restaurant Association had opposed the new law, arguing that legislators should not have the power to dictate what ingredients can be used in preparing restaurant food.

“Since people eat the vast majority of their meals at home, this will probably have a minor impact at this point in terms of overall public health and combating obesity,” said spokesman Daniel Conway.

Fast-food restaurants have not been alone in their quest to find the perfect-tasting substitute for artery-clogging trans-fat oils. Even higher end restaurants had to experiment with new alternatives, especially as pressure grew from consumers for more healthful food preparation.

Bernard Guillas, executive chef at the Marine Room in La Jolla, said his restaurant made a change in its frying oil about four years ago to a trans-fat-free canola oil.

“We also heavily use grapeseed oil for dressings and for frying,” Guillas said.

“My philosophy has always been to cook with really clean ingredients. You’re talking to a guy who had high cholesterol and I don’t have it any more. That trans fat really damages your arteries. It’s really, really bad. This will make a huge difference in our health care system because we’ll have less people getting sick. Everybody’s going to win.”

“We’re still faced with a significant obesity epidemic, and fast food is still highly caloric, but any improvement in these foods is welcome,” Ben-Yehuda said. “While we still have to be conscious of our caloric intake, without a doubt these foods were much more dangerous when they had trans fats.

“I’d much rather eat five pounds of butter than one pound of trans fats.”